Cisco IP Phone 7940 Manual

The Cisco IP Phone 7940 is a full-featured VoIP telephone designed for enterprise environments, supporting the Session Initiation Protocol (SIP) and Skinny Client Control Protocol (SCCP). It features a high-resolution pixel-based display, four programmable line/feature buttons, built-in headset and handset ports, integrated Ethernet switch, and support for Power over Ethernet (PoE) or external power. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting to Network 7. Basic Call Handling 8. Advanced Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Pixel-based LCD display, Handset, Four programmable line/feature buttons, Navigation button cluster, Speakerphone, Built-in Ethernet switch.

FeatureDescription
DisplayHigh-resolution pixel-based LCD with backlight
Line/Feature ButtonsFour programmable buttons for lines or features (e.g., hold, transfer)
HandsetStandard telephone handset with light indicator
SpeakerphoneFull-duplex speakerphone for hands-free calls
Headset Port2.5mm port for optional headset connection
Ethernet PortsTwo 10/100BASE-T RJ-45 ports (network and PC)
Power OptionsIEEE 802.3af PoE or external power adapter
ProtocolsSIP and SCCP firmware support
Navigation ClusterFour-way navigation with select button for menu access
Volume ControlRoller control for handset, speaker, and ringer volume

Installation

Unpack and inspect contents. Place phone on stable surface.

  1. Connect to network: Use Ethernet cable from switch to phone's SW port.
  2. Connect PC (optional): Use Ethernet cable from phone's PC port to computer.
  3. Provide power: Use PoE from switch or connect external power adapter to power port.
  4. Connect handset: Plug coiled handset cord into handset port.
  5. Connect headset (optional): Plug 2.5mm headset into headset port.

WARNING! Use only approved power sources. Ensure cables are securely connected.

First-Time Setup

Power on phone; phone will boot and attempt to obtain configuration from network.

  1. Network configuration: Ensure DHCP is enabled on network or manually set IP via settings menu.
  2. Verify registration: Check display for extension number and registration status.
  3. Set preferences: Use settings menu to configure time/date, ring tones, screen contrast.
  4. Program buttons: Assign line extensions or features (hold, transfer, etc.) to programmable buttons.

CAUTION! Do not disconnect power during firmware upgrade. Ensure proper ventilation.

Specifications

Controls and Settings

Access menus via navigation button. Front Panel: Handset, Speakerphone, Volume roller, Four programmable buttons, Navigation cluster (up/down/left/right, select), Messages, Settings, Help, Directory.

Softkeys: Context-sensitive buttons below display for call functions (e.g., Redial, Hold, Transfer).

Settings Menu: Network configuration (IP, subnet, gateway), Phone configuration (extension, SIP settings), User Preferences (ring tone, screen contrast, language).

Connecting to Network

Network: SW port to Ethernet switch. PC: PC port to computer.

  1. Ensure network switch supports VoIP traffic and QoS.
  2. Connect Ethernet cable from switch to phone's SW port.
  3. For daisy-chaining a PC, connect cable from phone's PC port to computer's Ethernet port.
  4. Power via PoE or external adapter.
  5. Phone will attempt DHCP; check display for IP address.

Tip: Use Category 5e or higher cables for optimal performance.

Basic Call Handling

Supports making, receiving, and managing calls.

  1. Make call: Lift handset or press Speakerphone, dial number, press Dial softkey or wait.
  2. Answer call: Lift handset, press Speakerphone, or press Answer softkey.
  3. End call: Hang up handset or press EndCall softkey.
  4. Hold: Press Hold button or Hold softkey during active call.
  5. Transfer: During call, press Transfer, dial target number, press Transfer again.
  6. Conference: During call, press Conference, dial second party, press Conference again.
  7. Redial: Press Redial softkey or dial ** to call last dialed number.
  8. Mute: Press Mute button during call to mute microphone.

WARNING! Do not use phone in wet conditions. Keep liquids away from device.

Advanced Features

Call Forwarding: Configure via settings menu or call server features. Speed Dials: Assign numbers to programmable buttons. Directory: Store personal directory entries. Messages: Access voicemail via Messages button. Network Statistics: View packet statistics in network settings.

Care & Cleaning

Unplug power before cleaning. Use slightly damp, lint-free cloth; do not use liquids or aerosols.

CAUTION! Do not spray cleaners directly on phone. Avoid abrasive materials.

Regulatory Information

FCC Part 15: Class A digital device; complies with limits for business environments. CE marked. For support, visit www.cisco.com or contact Cisco Technical Assistance Center. Copyright © Cisco Systems, Inc. All rights reserved.

Troubleshooting

SymptomPossible CauseCorrective Action
Phone not powering onPower sourceCheck PoE switch or power adapter connection; try different outlet.
No dial toneNetwork/registrationVerify Ethernet cable; check IP configuration; confirm registration with call server.
Poor audio qualityNetwork QoS/cablingEnable QoS on network; replace Ethernet cables; check for network congestion.
Display blank or dimPower/settingsAdjust screen contrast in settings; ensure power is adequate.
Buttons not respondingFirmware/defectReset phone; upgrade firmware; contact support if persistent.

Reset: Unplug power, wait 10 seconds, reconnect. For factory reset, press #** during boot (check admin guide).

Service: Cisco Technical Assistance Center; www.cisco.com

Cisco IP Phone 7940 Manual © - All Rights Reserved 2025